kernel/git/stable/linux.git/drivers/xen, branch linux-5.5.y

xenbus: req->err should be updated before req->state

2020-03-25T07:26:58+00:00

[ Upstream commit 8130b9d5b5abf26f9927b487c15319a187775f34 ] This patch adds the barrier to guarantee that req->err is always updated before req->state. Otherwise, read_reply() would not return ERR_PTR(req->err) but req->body, when process_writes()->xb_write() is failed. Signed-off-by: Dongli Zhang Link: https://lore.kernel.org/r/20200303221423.21962-2-dongli.zhang@oracle.com Reviewed-by: Julien Grall Signed-off-by: Boris Ostrovsky Signed-off-by: Sasha Levin

xenbus: req->body should be updated before req->state

2020-03-25T07:26:58+00:00

[ Upstream commit 1b6a51e86cce38cf4d48ce9c242120283ae2f603 ] The req->body should be updated before req->state is updated and the order should be guaranteed by a barrier. Otherwise, read_reply() might return req->body = NULL. Below is sample callstack when the issue is reproduced on purpose by reordering the updates of req->body and req->state and adding delay in code between updates of req->state and req->body. [ 22.356105] general protection fault: 0000 [#1] SMP PTI [ 22.361185] CPU: 2 PID: 52 Comm: xenwatch Not tainted 5.5.0xen+ #6 [ 22.366727] Hardware name: Xen HVM domU, BIOS ... [ 22.372245] RIP: 0010:_parse_integer_fixup_radix+0x6/0x60 ... ... [ 22.392163] RSP: 0018:ffffb2d64023fdf0 EFLAGS: 00010246 [ 22.395933] RAX: 0000000000000000 RBX: 75746e7562755f6d RCX: 0000000000000000 [ 22.400871] RDX: 0000000000000000 RSI: ffffb2d64023fdfc RDI: 75746e7562755f6d [ 22.405874] RBP: 0000000000000000 R08: 00000000000001e8 R09: 0000000000cdcdcd [ 22.410945] R10: ffffb2d6402ffe00 R11: ffff9d95395eaeb0 R12: ffff9d9535935000 [ 22.417613] R13: ffff9d9526d4a000 R14: ffff9d9526f4f340 R15: ffff9d9537654000 [ 22.423726] FS: 0000000000000000(0000) GS:ffff9d953bc80000(0000) knlGS:0000000000000000 [ 22.429898] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 22.434342] CR2: 000000c4206a9000 CR3: 00000001ea3fc002 CR4: 00000000001606e0 [ 22.439645] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 22.444941] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 22.450342] Call Trace: [ 22.452509] simple_strtoull+0x27/0x70 [ 22.455572] xenbus_transaction_start+0x31/0x50 [ 22.459104] netback_changed+0x76c/0xcc1 [xen_netfront] [ 22.463279] ? find_watch+0x40/0x40 [ 22.466156] xenwatch_thread+0xb4/0x150 [ 22.469309] ? wait_woken+0x80/0x80 [ 22.472198] kthread+0x10e/0x130 [ 22.474925] ? kthread_park+0x80/0x80 [ 22.477946] ret_from_fork+0x35/0x40 [ 22.480968] Modules linked in: xen_kbdfront xen_fbfront(+) xen_netfront xen_blkfront [ 22.486783] ---[ end trace a9222030a747c3f7 ]--- [ 22.490424] RIP: 0010:_parse_integer_fixup_radix+0x6/0x60 The virt_rmb() is added in the 'true' path of test_reply(). The "while" is changed to "do while" so that test_reply() is used as a read memory barrier. Signed-off-by: Dongli Zhang Link: https://lore.kernel.org/r/20200303221423.21962-1-dongli.zhang@oracle.com Reviewed-by: Julien Grall Signed-off-by: Boris Ostrovsky Signed-off-by: Sasha Levin

xen: Enable interrupts when calling _cond_resched()

2020-02-28T16:23:44+00:00

commit 8645e56a4ad6dcbf504872db7f14a2f67db88ef2 upstream. xen_maybe_preempt_hcall() is called from the exception entry point xen_do_hypervisor_callback with interrupts disabled. _cond_resched() evades the might_sleep() check in cond_resched() which would have caught that and schedule_debug() unfortunately lacks a check for irqs_disabled(). Enable interrupts around the call and use cond_resched() to catch future issues. Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted") Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/878skypjrh.fsf@nanos.tec.linutronix.de Reviewed-by: Juergen Gross Signed-off-by: Boris Ostrovsky Signed-off-by: Greg Kroah-Hartman

xen/gntdev: Do not use mm notifiers with autotranslating guests

2020-02-11T12:37:06+00:00

commit 9293724192a73f49c722e9685d45649c6df67dfe upstream. Commit d3eeb1d77c5d ("xen/gntdev: use mmu_interval_notifier_insert") missed a test for use_ptemod when calling mmu_interval_read_begin(). Fix that. Fixes: d3eeb1d77c5d ("xen/gntdev: use mmu_interval_notifier_insert") CC: stable@vger.kernel.org # 5.5 Reported-by: Ilpo Järvinen Tested-by: Ilpo Järvinen Signed-off-by: Boris Ostrovsky Reviewed-by: Jason Gunthorpe Acked-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman

xen/balloon: Support xend-based toolstack take two

2020-02-11T12:37:06+00:00

commit eda4eabf86fd6806eaabc23fb90dd056fdac037b upstream. Commit 3aa6c19d2f38be ("xen/balloon: Support xend-based toolstack") tried to fix a regression with running on rather ancient Xen versions. Unfortunately the fix was based on the assumption that xend would just use another Xenstore node, but in reality only some downstream versions of xend are doing that. The upstream xend does not write that Xenstore node at all, so the problem must be fixed in another way. The easiest way to achieve that is to fall back to the behavior before commit 96edd61dcf4436 ("xen/balloon: don't online new memory initially") in case the static memory maximum can't be read. This is achieved by setting static_max to the current number of memory pages known by the system resulting in target_diff becoming zero. Fixes: 3aa6c19d2f38be ("xen/balloon: Support xend-based toolstack") Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Cc: # 4.13 Signed-off-by: Boris Ostrovsky Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-linus-5.5b-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2019-12-21T14:24:56+00:00

Pull xen fixes from Juergen Gross: "This contains two cleanup patches and a small series for supporting reloading the Xen block backend driver" * tag 'for-linus-5.5b-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/grant-table: remove multiple BUG_ON on gnttab_interface xen-blkback: support dynamic unbind/bind xen/interface: re-define FRONT/BACK_RING_ATTACH() xenbus: limit when state is forced to closed xenbus: move xenbus_dev_shutdown() into frontend code... xen/blkfront: Adjust indentation in xlvbd_alloc_gendisk

xen/grant-table: remove multiple BUG_ON on gnttab_interface

2019-12-20T12:54:56+00:00

gnttab_request_version() always sets the gnttab_interface variable and the assertions to check for empty gnttab_interface is unnecessary. The patch eliminates multiple such assertions. Signed-off-by: Aditya Pakki Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross

xenbus: limit when state is forced to closed

2019-12-20T12:44:38+00:00

If a driver probe() fails then leave the xenstore state alone. There is no reason to modify it as the failure may be due to transient resource allocation issues and hence a subsequent probe() may succeed. If the driver supports re-binding then only force state to closed during remove() only in the case when the toolstack may need to clean up. This can be detected by checking whether the state in xenstore has been set to closing prior to device removal. NOTE: Re-bind support is indicated by new boolean in struct xenbus_driver, which defaults to false. Subsequent patches will add support to some backend drivers. Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross

xenbus: move xenbus_dev_shutdown() into frontend code...

2019-12-20T12:44:35+00:00

...and make it static xenbus_dev_shutdown() is seemingly intended to cause clean shutdown of PV frontends when a guest is rebooted. Indeed the function waits for a conpletion which is only set by a call to xenbus_frontend_closed(). This patch removes the shutdown() method from backends and moves xenbus_dev_shutdown() from xenbus_probe.c into xenbus_probe_frontend.c, renaming it appropriately and making it static. NOTE: In the case where the backend is running in a driver domain, the toolstack should have already terminated any frontends that may be using it (since Xen does not support re-startable PV driver domains) so xenbus_dev_shutdown() should never be called. Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross

Merge tag 'for-linus-5.5b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2019-12-15T20:24:44+00:00

Pull xen fixes from Juergen Gross: "Two fixes: one for a resource accounting bug in some configurations and a fix for another patch which went into rc1" * tag 'for-linus-5.5b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/balloon: fix ballooned page accounting without hotplug enabled xen-blkback: prevent premature module unload